While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Citrix Systems (NASDAQ:CTXS) bounced back 2% this morning after Nomura Securities upgraded the cloud computing company from neutral to buy.

So what: Along with the upgrade, analyst Rick Sherlund planted a price target of $70 on the stock, representing about 31% worth of upside to yesterday's close. While momentum traders might be turned off by yesterday's earnings-related drop, Sherlund believes Citrix's risk/reward trade-off is now too cheap to pass up.

Now what: Nomura expects Citrix to post 2014 and 2015 earnings per share of $2.87 and $3.18, respectively. "Overall company revenue growth of 8% is coming largely from lower gross margin NetScaler, so the mix shift is creating some near-term margin pressure," Sherlund noted. "We think the low valuation provides some downside protection and there are a number of things that could go right that are not likely reflected in the share price." With Citrix shares off about 30% from their 52-week highs and trading at roughly four times recurring maintenance and subscription revenue, it's tough to disagree with Nomura's bullishness.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.